NASA to test Endeavour external tank

NASA plans to conduct a test of space shuttle Endeavour’s external fuel tank at the Kennedy Space Center in Florida to make sure repairs were successful.

The test will be shown live online by NASA TV beginning at 7 a.m. EDT Wednesday.

During the test, the external tank will be filled with liquid hydrogen and liquid oxygen, just as it is before launch, the space agency said in a statement. A hydrogen gas leak at the Ground Umbilical Carrier Plate “¦ postponed Endeavour’s launch attempts June 13 and 17. The GUCP is attached to the venting system used to carry excess hydrogen safely away from the launch pad.

NASA engineers said the leak was likely caused by a slight misalignment in an assembly that put uneven pressure on a Teflon seal, causing a small leak when extremely low temperatures occurred during fueling. The old seal was replaced with a two-piece seal and engineers added small washers to counter any movement during fueling.

Endeavour’s STS-127 mission is targeted for launch at 7:39 p.m. EDT Saturday, July 11. The 16-day mission to the International Space Station will feature five spacewalks and complete construction of the Japan Aerospace Exploration Agency’s Kibo laboratory.

Information about NASA TV streaming video, downlink and schedule information is available at http://www.nasa.gov/ntv.